A popular aspect of virtual worlds such as Second Life, There.com, and World of Warcraft is socializing. Such socializing involves meeting up with new contacts and keeping track of them. But a challenge is finding these contacts if they are in a virtual world at the same time as you, getting more information about these contacts, and initiating in-world actions with these contacts. Current solutions to these challenges can be classified as follows:
IM Style Buddy Lists: Probably the most prevalent approach is borrowed from IM (Instant Messaging) clients such as AIM (AOL Instant Messaging) and Lotus Sametime, which use a 2-D list of names with additional metadata. The metadata includes whether the contact is in-world or not, in-world location details, a phone number to call, and a photo. The list may have actionable buttons or context menus to perform actions such as initiate a chat, invite to a group, or invite the recipient to teleport to your location. This is featured in many games and virtual worlds like Second Life, World of Warcraft, IMVU, etc. The strength of this approach is the re-use of a familiar user-interface metaphor from IM systems. The main drawback of this approach is that it distracts the user from the immerse 3-D environment: the list is presented as a fullscreen display, a floating dialog window, or a sidebar window, and the list does not leverage the innate properties of the actual virtual environment.
Virtual Contact Objects: A less common approach is to create an in-world object that provides the same data as one or more contacts in an IM-style buddy list, and the object can be manipulated by an avatar to perform actions such as initiate a chat, invite to a group, or teleport people to other people's locations. The strength of this approach is the representation of contacts as actual manipulable virtual objects. The main drawback of this approach is that the owner of the object needs to remember to instantiate the object and give it to a recipient, much like the process of giving a business card in the real world. Another problem is the recipient of the object must remember to find the object and bring it up to make use of the metadata (such as to find out whether the contact is present in-world or not).
Online Presence Visualization: Some of the metadata of contacts can be displayed as in-world or heads-up-display visualizations portraying the presence of contacts in the virtual world. For example, in many first-person shooter games (as well as virtual worlds like Second Life), a top-down map or radar overlay presented in the user interface can show where contacts are within range of the user as dots. The dots can be annotated with names and other data. Another example is the use of footprints or trails in the sky (see Drew Harry's Information Spaces work at web.media.mit.edu/˜dharry/infospaces/full_description.html)—where potential contacts leave behind a visible floating trail in the sky. The strength of this approach is the ability for visualization to provide a quick visual summary of activity in the virtual world. The main drawback of this approach is that there is a limit of how much metadata can be portrayed in a visualization, and if the contact is offline, then there is nothing to visualize and hence the user cannot retrieve the metadata.